Clutch



Oct. 17, 1933. Q L, LAWSON 1,930,482

CLUTCH Filed oet. 2o, 1951 I Patented Oct. 17, 1933 UNITED STATE s Y f CLU'roHff, ,f Oscar L. Lawson, Lynn, Mass., assignor to Unitedl Shoe Machinery Corporationlaterson, N. 1J.,

va corporation of New Jersey Application october zo, 1931. Seriana-569343' 4 Claims.` (o1.192f`s1) 1 L a driven member present certain diiiiculties duev to the fact that theV coil should engage the hub rmly and uniformly at all points while atthe same time the force applied to the coil to contract it should at no time be suiiicientV to break the coil. The general object of the present invention is to provide a clutch of the coil type in which these difliculties are avoided, the invention consisting of certain details of construction and combinati-ons 1,5 of parts which will be described as embodied in an illustrated device and pointed out in the appended claims.

Referring now to the accompanying drawing, Fig. lis an elevation of a clutch in which the present invention is embodied; and K Fig. 2 is a perspective of certain portions of the clutch. Rotatably mountedon the shaft 3 and held from longitudinal movement with respect thereto 2o is aV driving member 5 having formed upon it a gear 7 by which it may be rotated continuously, said driving member having a hub 9 which is encircled by a contractible coil 11 of spring steel. A driven member 13 has a cup-shaped portion extending over the coil and a hub which is fastened to the shaft by set screws 15. Integral with the coil are two lugs 17, 19, one located near one end of the coil and the other located near the other end, the member 13 being formed with a suitable hollow boss to receive the lugs loosely so that.

rection. The axis of this screw is oblique to the axis of the lug, and the conical end of the screw engages a flat face on the lug so that by turning the screw the coil may be adjusted into different angular positions about the hub, a check-nut 23 being provided to hold the screw in adjusted position. The purpose of this adjustment is to vary the extent to which the coil will be contracted about the hub 9 when pressure is applied t-o the g other lug 19 in a manner presently to be de- UO scribed.

This other lug is engaged by one end of a small pin 25 which is slidable in a bore in the driven member 13, the other end of the pin being held by I a small spring 26 in contact with the operative u" end of a two-armed lever 27 pivoted about a pin 29 carriedk by theV driven" memberv 13;,v YConsequentlyywhen this lever is rocked ina` counterclockwise direction, asviewed inF-ig. 1, the coil is contracted about the hub-of the driving member 45 and the'shaft 3,-is rotated.A This ,rocking 30 movementis accomplished yeldi'n'glyby means of i a second two-armed leverialso'fpivoted about the pin 29 and having twozarms S31, 33 saidftwoarmed lever serving asv an actuator `for the twoarmed lever 27. Fastened to the upper end of 65 one arm'of the two-armed lever 27 isa bolt 35,

Vthe stem of thislbolt passing loosely 4through a bore in the outer end-'ofthe arm-31 of the other lever; A comparatively heavy coiled spring 37 encircles the stem ofthe bolt 35 between thehead 7o `of the bolt and one face of. the arm 31'., When, now, the arm 33 is rocked away from theshaft 3, the arm `31, through the spring 37 and bolt 35 'rocks the two-armed lever 27 to force the-pin 25 against-the lug 19 and thereby to contract the 75 coil 1'1 about "the hub 9, the parts. beingshown in these positions in the figures. 1 In order to factuate the arm '-33,'.afspoolj39, which'is loose onthe shaft`3, has a tapered portion 39' to engage the free end of the arm 33 so and swing said arm, said spool having a circumferential groove l1 to receive rolls carried in the usual manner by the arms of a shifting fork 43 pivoted about a stationary pivot 45. This shift'- ing fork 43 has an extension 43 adapted to` be engaged by the free end of a pivoted treadle 47 or other suitable member.

When the parts arer in the positions shown, the treadle is being held depressed about its pivot with its free end raised as shown, and the clutch is engaged. When the treadle is released, the weight of the extension 43 swings the shifting fork 43 to the left, as viewed in Fig. 1, to slide the spool 39 to the left and thereby disengage the clutch. In order to hold the free end of the arm 33 at all times in engagement with the spool 39, a small compression spring 49 bears with one end against the bottom of a socket in the driven member 13 and with the other against the bottom of an alined socket in the two-armed lever 27.

It should be particularly noted that the force which is applied to the lug 19 to contract the coil is a yielding one due to the presence of the spring 37 and that the screw 21 provides means forA adjusting the coil circumferentially of the vhub 9. This coiled spring is of such strength that when the two-armed lever 31, 33 is swung through its path of iixed extent into the position shown, the spring 37 is compressed very 110 the two two-armed levers.

slightly, if at all, and the coil 11 is contracted just enough to engage the hub 9 rmly. The adjustment of the parts to secure this desirable result in the first instance is made by turning the adjusting screw 21 which locates the coil circumferentially of the hub and by turning the screw 35 which changes the relation between It is very desirable that the compression of the spring 37 in the position of parts shown should alwaysV be substantially the same so that, on the one hand, the coil 11 will engage the hub firmly and, on the other hand,` the coil will not be contracted enough to cause it to break. When the friction between the coil and the hub wears these partey so that the clutch does not hold properly, the adjusting screw 21 is turned so that the tension of the spring 37 in the position o! parts shown will re main substantially as it was before the wear took place. f

Although the yinvention has beenl set forth as embodied in a particular. device it should be understood that the invention is not limited in the scope of its. application tothe particular device which has been shown and described.

Having thus described my invention, what I claim as new and desire to secure byLetters Patent of the United States is:l f 1. A device of the class describedhavng, in combination, a shaft,.a driving member loosethereon and providedv with a hub, a ccntractible coil encircling the.v hub and provided with two lugs spaced from each otheralong ,the coil, a cupshaped member extending over the coil and fast to the shaft, an adjusting screw carried bythe cup-shaped member and engaging one lug on the coil, a two-armed lever pivoted on the cup-shaped member, a pin located between the end of one arm of the lever and the other lug on the coil, and yielding means engaging the other armof the lever for swinging saidlever about-itsvpivot to contract the coil about the hub. Y 2.1A device of the class described having, in combination, a shaft' a. driving member loose thereon and provided with a hub, a contractible coil encircling the hub and provided with two lugs spaced from each other along the coil, an adjusting screw in contact with one lug, a movable member in contact with the other lug, an actuator for said member, means for moving said actuator in a path of fixed extent, an adjustable yielding connection between the actuator and the member, and operator-controlled means for moving the actuator.

3. A device of the class described having, in combination, a shaft, a driving member loose thereon and provided with a hub, a contractible coil encircling the hub and provided with two lugs spacedfrom each other along the coil, a member extending over the vcoil and fast to the shaft, an adjusting screw carried by the member and engaging one lug on the coil, a lever pivoted on the member and adapted when swung about its pivot to contract thecoil, an actuator also pivoted on the member, and a yielding adjustable connection between the actuator and the lever.

4. A device of the class described having, in combination, a shaft, a driving member loose thereon and provided with a hub, ay contractible coil encircling the hub and provided with two lugs spaced from each other along the coil, a cupshapedemember extending over the coil and fast to the shaft, an adjusting screw carried by the cup-shaped member andengaging one lug on the coil, a twolarrned lever, a pivot carried by the cup-shaped member upon whichthe lever is mounted, a pin located between the end of one arm of thelever and the otherlug on the coil, and means for swinging thelever about the pivot to contract the coil about the hub, said means comprising la second two-armed lever mounted on the same pivot upon which the first-named lever is mounted, a yielding connection between an 'arm of one lever and an arm of the other lever, and means for engaging the free arm of the second named lever to swing it about the pivot. Y Y

oscAR L. LAwsoN. 

